Conventional turbine flow meters utilize a rotor for measuring the flow rate of a fluid. These conventional turbine designs utilize a rotor that is aligned to the flow path of the fluid being measured. That is, the general direction of the entering flow is aligned with the axis of the rotor. Such rotors have blades that are generally positioned angularly to the flow path. As the velocity of the fluid increases, the rotor will rotate. The speed of rotation of the rotor is proportional to the velocity of the fluid passing across the rotor.
It is quite difficult to mechanically measure fluid flow at low fluid velocities with conventional turbine flow meters. One of the problems in precisely measuring low flow rates with a mechanical device is that the flow meter must overcome the effects of friction and inertia. That is, the velocity of the fluid being measured must be sufficient to overcome the effects of friction and inertia in order for the flow meter to properly function and to measure relatively low flow rates.
Therefore, there has been and continues to be a need for a turbine type flow meter that will precisely measure low flow rates.